Icom Receiver with a Collins 32V2 transmitter.

[k6hsg]

I recently bought an Icom 7600 hoping to use it to get AM.   I also have a Collins 32v2 transmitter. I have been listening to the AM guys at the high end of the 40 meter band.  Around 7.290.  I tried braking in with the 7600 transmitter with no luck.  I heard a guy in San diego with  an Icom 718 and he was having no problem but I am showing a swr of 3+ and am worried about doing damage to the final on the 7600 if I run the power up to the maximum .
 So I thought that I would use the 7600, which has an unbelievable receiver, as my receiver and use the 32V2 when transmitting.
 What I am worried about is doing damage to the front end of the 7600 when transmitting.
I have a Drake coaxial switch,  local and antenna, and will be switching the antenna between the two with it using the local function of the switch.
I have the two devices on the 1 and 3 positions to separate them a bit in the switch.
Will this be sufficient or do I need to something else.

I have a Hammarlund Super Pro that I have been working on for ever that I plan to use with the Collins but I am getting older and would love to get on the air

73, John

[Pete, WA2CWA]

You shouldn't run more then 25 watts in the AM position with the IC-7600. If the antenna tuner in the 7600 can't get the SWR down to some low value, you need to work on the antenna. 25 watts on AM can work on 40 meters but it can be marginal unless you have a good antenna to make up the difference. A linear works well with the 7600. Using the 7600 as a separate receiver would work but I would definitely ground the receiver input when transmitting with a separate transmitter. A believe the 7600 front end is fuse protected, but if you blow the fuse, you have to open the rig up and dig around the boards to replace it.

[WD8KDG]

Get the SWR down! There seems to be a group in Mexifornia around 7.293. Here in the Pacific Northwest 7.294 has some activity.

Stations running a single 6146 (40 watts output) boom in. Mobils using IC-706's are heard.

Fix the antenna system,

Craig,

[WQ9E]

Your coax switch will provide sufficient isolation but it isn't very convenient.  A relay controlled by the 32V-2 would be preferable and if you don't have one already even Radio Shack still carries a suitable one in their stores:  http://www.radioshack.com/product/index.jsp?productId=2049721

I am not familiar with the 7600 and I don't know if it has an external muting port.  If so the extra set of contacts in the relay can be used for that and if not you can use the second set of contacts to ground the receiver input when in transmit.  If you have a 4PDT relay with 120 volt coil then it will have enough contacts to mute the receiver and ground the receiver antenna input during transmit.

[W3GMS]

Hi John,

I use a Ten Tec Jupiter transceiver as a receiver with my Johnson Ranger.  It has no provision for muting but I found a good work-around.  When I want to mute the Jupiter, I put the Jupiter in the transmit mode with the PTT but within the Jupiter's menu there is a provision to turn off the transmitter.  So when the Ranger gets keyed, a set of contacts engage the Jupiter's PTT but the transmitter is disable through the menu.  If your rig allows the power to be set to zero, you may be able to do a similar thing.

Joe, W3GMS

[kb3ouk]

Hi John,

I use a Ten Tec Jupiter transceiver as a receiver with my Johnson Ranger.  It has no provision for muting but I found a good work-around.  When I want to mute the Jupiter, I put the Jupiter in the transmit mode with the PTT but within the Jupiter's menu there is a provision to turn off the transmitter.  So when the Ranger gets keyed, a set of contacts engage the Jupiter's PTT but the transmitter is disable through the menu.  If your rig allows the power to be set to zero, you may be able to do a similar thing.

Joe, W3GMS

I know my Icom 718 allows the same thing, I know that the 718 has two menus, quick set and initial set, the setting to disable transmit is under initial set. I believe the 718 also allows transmit disable by mode, so i could disable AM transmit but still have SSB and CW. I'm curious to see if the 7600 does the same thing.

[k6hsg]

Thank you for all of the excellent advice.
I have looked through the 7600 manual which is a little on the poor side.
It has no index and is not laid out very well but that's another problem.
I haven't found a way to shut off transmit but I did learn how to use the
tuner and it does tune to a swr of 1.
The 7600 puts out 30 watts on am.
I am going to try it out tomorrow and see if I can raise somebody.
73, John